This invention relates generally to a particle collector adapted to remove and collect particles entrained in an air stream.
More particularly, the invention relates to a collector of the type having a relatively large container for the collection of particles, having a lid formed with inlet and outlet openings adapted to allow the air stream to flow into and out of the container, and relying on a reduction in the velocity of the air stream as the air stream enters the collector and on turbulence of the air in the container to cause the particles to separate from the air without the need of a filter element. Collectors of this type are particularly suitable for use as the first stage of a two-stage collection system where the second-stage collector is adapted to remove relatively fine particles and dust from the air stream and where the volume of relatively large particles entrained in the air is substantially greater than the volume of the entrained dust and fine particles. For example, a two-stage collection system of this type is particularly useful in collecting the dust and wood chips generated by power tools such as planers, saws, and the like.
In a typical two-stage dust and wood chip collection system, a shroud is located near the power tool and is adapted to trap the dust and wood chips in a confined area. A flexible hose or so-called pickup hose connects the shroud with the inlet of the first-stage collector. A second hose or so-called suction hose connects the outlet of the first-stage collector with the inlet of the second-stage collector. An electric blower draws air from the inlet of the second-stage collector so as to create a vacuum upstream of the second-stage collector. The electric blower is typically part of the second-stage collector. For example, the second-stage collector may be a common household-type shop vacuum. Alternately, the second-stage collector may be an industrial-type single-stage or two-stage collector.
With the foregoing arrangement, the vacuum draws the dust and wood chips away from the shroud and into the top of first-stage collector by way of the pickup hose. As the air flows through the first-stage collector, the relatively large particles fall from the air stream and collect in the container. The dust and smaller particles pass through the first-stage collector and are carried to the second-stage collector by way of the suction hose. The air stream exits the second-stage collector through a filter element which traps the dust and the relatively small particles.
A principle advantage in the use of a two-stage collection system of this type is the ability to reduce the downtime of the system due to the need to dispose of the collected waste. While the second-stage collector is capable of collecting all of the dust and the wood chips generated by the power tool, the second-stage collector typically includes fasteners which must be disengaged in order to empty the collector. The first-stage collector, on the other hand, is capable of collecting the bulk of the waste and is capable of being disassembled and reassembled relatively quickly and easily. The lid of the first-stage collector is typically adapted to rest on top of the container. Advantageously, the vacuum created by the blower holds the lid in place when the collection system is operating. This arrangement permits the lid to be simply raised off of the container to enable emptying of a full container or replacement of a full container with an empty container after the blower has been turned off.
Prior lids adapted for use in first-stage collectors are typically formed with generally vertically facing inlet and outlet openings. As a result, the air stream flows into the container in a generally downward direction and the air is drawn out of the container in a generally upward direction. With the outlet opening being in relatively close proximity to larger particles which may be circulating in the container, the outgoing air tends to draw these larger particles out of the container.
Moreover, if the level of particles collected in the container is relatively high, the downwardly directed incoming air stream resulting from these prior lids tends to impinge directly onto the collected particles and tends to cause some of these particles to be lifted into the turbulent air in the container. As a result, as the level of the particles collected in the container rises, the tendency for the larger particles to be lifted and carried out of the container by the outgoing air increases.
Further, in some types of second-stage collectors, the particles must pass through the impeller of the blower before they are removed from the air stream or trapped by the filter element. In this instance, the noise level of the blower increases and the likelihood of damage to the blower from relatively large particles increases as the efficiency of the first-stage collector decreases.